Power transmission mechanism



June 7, 1932. N LE'GGE 1,862,188

POWER TRANSMISSION MECHANISM Filed April 30, 1931 NVENTOR 4 BY m M ATTORNEYS Patented June 7, 1932 UNITED sTAT s PATENT Neuron LEGGE, or nnxmmnnenann J rowERrBANsr/ussmrr 'mnenamsm" Application filed April 30, 1931, Serial No.

member, a movable intermediate 'member whose function it is to transmit the drive 15 from the driving to the driven member,

matically take up the drive when therelative speeds of the driven and driving members synchronize. V A control is not necessarilyrequired for the operation of the device, but a an external control is conveniently incorporated to provide a solid drive, when desired. A subsidiary uni-directional drive J is employed for coupling the driving, memlow ready mutual engagement without clashing of the aws.

of a very slight relative rotation between 9 these membersto take up Working clearances between the teeth of the intermediate and driving members.

The accompanying drawing illustrates'one example of overrunmng and synchronizing ing shaft which is provided with a hollowen-;

largement 11, and 12 is the drivenshaft'which' extends into said enlargement, the axes of, said shafts bemg in alignment. 13 is a staand an automatic cont-rolling member for causing said intermediate member to autober and the controlling member, and is-arc-i, ranged so as to ensure that theteeth on the driving and intermediate members'take up definite rotational positions when" the driv- 3 ing and driven members synchronize, to al The coupling between the" controlling and intermediate members allows" 533,998,,and in Great Britain'lfiay 6,1930,

tionaryb casing enclosing the device The shafts and 12 run in ball bearings 14 and 15mounted withinsaid casin and theend of the shaft1 2 nearer the sha 10' runs in a bush 16 within the enlargement 11. c The 55 shaft 12 has a quick-pitched helical thread 17 r of suitable direction separated by a collar 18 from a-ring of axial keyways19 in the shaft 12, said keyways receiving the internal teeth 20 of a sliding dog clutch element2l surrounding the said shaftand provided'for the purposeof obtaining asolid drive. c. 1; I i-Mounted on the'thread 17 is an interna ythreaded intermediate member 22 which can travel axially between the collar 18 and .21 5 I controlling member23 mounted around: a plain portion 24 of the shaft 12. The intermediate member 22, hastwo-ringsof radial teeth 25 and 26. A spring. 27 is interposed between. the member 22v and the collar 18 so 7 that, duringoverrunning periods, said member is kept away from saidcollar. The col-, lar 18 takes the driving thrust.

-The hollow enlargementll of'the driving shaftis provided 'with'ringsofinternalteeth 28 and 29, the teeth'29 'co-operatin' with the. teeth 251011; the member 22, and the 0g clutch element 21 is provided with a ringflof teeth 30 co-operating with the teeth 26 .on the mem- 1 r so The controlling member 23- carries a plurality of pawls 31 q-pressed outwardly by springs 32 intoengagementiwith the teeth 28, and-said controlling inember'23 and the intermediate member 22 vare coupled together by pins 33 mounted in=the member 23' and 'prO ecting into axial holes 34in the member 22. The positionsof the rpins 33'and holes 34 maybe interchanged. The member23 is partly rotatableon the shaft 12, but normally it rotates with said shaft. It willbe noticed that the member23- can freely overrun the teeth 28 in the direction indicatedbythe arrow45 in Fig. 2, the pawls 31 riding over the teeth, but the member 23 cannot beoverrun bythe teeth 28in the said direction which 'is Q 1 the normal forward direction of rotation. The pawls 31 thus provide a subsidiary unidirectional drive betweenthe driving shaft 1- 1O .and'the controlling member"23.1 T 0 per mit the necessary small working backlash between the teeth 25 and 29, the pins 33 have tapered points, and when the teeth 25 and 29 are in engagement, the intermediate member 22 is in its right hand position and con sequently theholes 34 are in engagement with the tapered portions of the pins. 'Henceit will be clear that a very small relativerotation is then possible between the members 22 and 23 and the teeth 25, 29 are then enabled to take up working clearances and make metal-to-metal engagement with oneanother, thus ensuring that the main drive to the shaft 12 is transmitted through these teeth and not through'the pawls 31 and teeth 28. Except for the slight relative rotation above mentioned, the intermediate member'22 cannot 2 the direction indicated by the arrow 45, the,

rotate-relatively to the controlling member 23 v.but it is free to move axially.

. he subsidiary uni-directional drive ensures that the intermediatemember 22 and the controlling member 23 are always located in definite rotational positions in relation to the teeth 29 when the speeds of the shafts v10 and 12 synchronize and the pawl 31 has engaged one ofthe teeth 28, and ready mutual engagement of the teeth 25,29 is thus obtained. For this purpose, the number of teeth 28-is made teeth 29.

The action of the'device is as follows On the shaft 10 commencing to revolve in shaft '12 being stationary, the movement is transmitted by the teeth 28 and pawls 31 to the controllin pins 33 to the intermediate member 22 which at once runs up the thread 17 against the collar 18..and its teeth 25 enga e the driving '25, 29 disengaged while the shaft 12 over teeth 29, whereupon the slig t slip due to the tapered portions of the pins 33 being now in the holes 34 provides clearance between the pawls 31 and the teeth 28, and the teeth' 29 and 25 take up the drive. v

' When the shaft 12 commences to overrun the driving shaft 10, the intermediatemember 22 (which, by reasonof the engagement of the teeth 25, 29. is revolving at the same speed as the shaft 10) is forced to travel'to the leftalong. the thread 17 which for the moment overruns the member 22. This travel of the member 22 disengages the teeth.

25, 29 and'uncouples the shaft 10 from the shaft12. .The sprin 27 maintains the member 22 in its left han position withthe teeth runs the shaft 10, and the pawls 31 ride over the teeth 28.. i H w When the shaft 10is again speeded up and arrives at the point when'its speed synchronizes with that of the shaft 12, it has a momentary tendency to pass the latter, but the subsidiaryuni-directional drive provided by the teeth 28 and pawls 31 acting between the drivingshaft'lO and the controlling member ,ment.

equal to the number of the" member 23 and through the 23 causes the latter and hence (by reason of the coupling pins 33) the intermediate member 22 to momentarily partly overrun the shaft 12 whereupon the intermediate member is compelled to travel to the right along the thread 17 and re-engage the teeth 25 and 29 and the drive is a ain positively established between the sha" t 10 and the shaft 12.

For locking the mechanism for a solid drive, the dog clutch element 21 is slid to the left by a shoe 35 engaging a peripheral groove 36 around the clutch, said shoe being mounted on an arm 37 keyed on a spindle 38 which can be rocked from outside the casing 13 by a lever 39, this movement of the clutch element engaging'its teeth 30 with the teeth 26 of the intermediate member (when said member is in its right hand position with the teeth 25 and 29 engaged) while not disengaging the teeth 20 from the keyways 19 teeth 25 and 29 cannot disengage so long as the teeth 26', 30 are maintained in engage- It will be noticed that, with this construction, it is impossibleto clash theteeth 26 and 30 when engaging'them for a solid drive as these teeth must be revolving at the same speed.

-Wi th reference to the subsidiary uni-directional drive mechanism, it may be desirable in some cases to so arrange this mechanism that contact between the pawls 31 and the teeth 28'lS reduced or avoided while the shaft 12 is overrunning the driving shaft 10 there-' by reducing noise and wear between the pawls and teeth. This result is attained by means of the ball or-roller bearing'40, the outerrace 41 of which is mounted on the enlargement 11' and the inner race 42 on a floating flanged bush 43 provided with tongues 44 which abut against the pawls 31 as shown in Fig. 2. This arrangement utilizes the inertia of the floating inner race 42 andfl'anged bush 43 and the slight drag between the races 41 and 42. the floating bush 43 from revolving with the race 41-, and,in so doing, are prevented from engaging with the teeth 28, and are kept out of action until overrunning ceases and consequently the drag between the two races 41 and 42 also ceases, due to both the races then tending to revolve at the same speed. The

pawls 31 are then free to engage with the teeth 28 under the action of their springs 32 when the dragging action momentarily-tends to. be reversed in direction as the driver is on the point of taking up the load automat-' The'pawls 31 themselves restrain;

terchangeable, that is,the shaft 12 provided with the thread 17 may become the driving member and the shaft may become the driven member. The positions of the pawls 31 and teeth 28 may also be interchan' ed.

What I claim and desire to secure y Let-- ters Patent is 1. An overrunning and synchronizing dc vice comprising a rotary driving member, teeth therearound, a rotary driven member, ahelical thread thereon, an axially-travelling internally-threaded intermediate member on said thread, teeth around said intermediate member co-operating with said driving teeth,-

a controlling member on saiddriven' member adjacentto saidthread, a: subsidiary unidirectional drive between said driving member and said controlling member,and means for coupling said controlling member and said intermediate member together,

2. An overrunning andesynchronizing de-. vice comprising a rotary driving member,

teeth therearound, a rotary driven member,

a helical thread thereon, an ax ally-travelling internally-threaded intermediate member on said thread, teeth around said intermediate member co-operating with said driving teeth, a controlling member on said dr ven member adjacent tosaid thread, a subsidiary unidirectional drive between said driving member and said controlling member, sa d subsidiary uni-directional drive being positioned so that the teeth mediate members are located in defin te rotational positions when the speed of the rotary driving member and the dr ven member synchronize, and means for couplingsaid controlling member and said intermediate mem-' v berto ether.

40, a helical thread thereon, an axially-travel- 3. n overrii ining and synchronizing device comprising a rotary driving member, teeth therearound, a rotary driven member,

linginternally-threaded intermediate member on said thread, teeth around said intermediate member co-operating with said driv in teeth, a controlling member on said driven member adjacent to said thread, a sub- 7 vice comprising a rotary driving member, teeth therearound, a rotary driven member, a helical thread thereon, an axially-travelling internally-threaded intermediate member on saidthread, teeth around said inter- ,of the driving and intersaid controlling memmediate member co-operating with said drivin teeth, a controlling member on said driven member adjacent to said threadga subsidiary unidirectional drive between said;

driving member and said controlling member, said subsidiary unidirectional drive bc-' ing positioned so thatthe teeth of the drivin and intermediate members are located'in de inite rotational positions when the speed of the. rotary driving member and the driven member synchronize, and means .for coupling said controlling member and said 'interme diate member 'togethensaid coupling means permitting the slight rotation necessary to 7 take uworking clearances between the teeth' of the intermediate and driving members and Q comprisingtapered projections.

5. An overrunning and synchronizing device-comprising a rotary driving member,

teeth therearound, a rotary driven member, a helical thread thereon, an axially-travel ling internally-threaded intermediatev mein ber on said thread, teeth around said intermediate member co-operating with said drive ing teeth, a' controlling member on said driven member adjacent to said thread, a subsidiary unidirectional drive between said driving member "and said controlling 'memher, said subsidiary unidirectional drive be e in g positioned so that the teeth of the driving and intermediate members are located in def inite rotational positions when the speed of the rotary driving member and the driven member synchronize, and means for coupling said controlling member and said-intermediate member together, said couplingmeans' permitting the slight rotation necessary to take up working clearances between the teeth of the intermediate and driving members and comprising tapered projections, and means for locking said intermediate member to said driving memberto obtain a solid drive."

An overrunning and synchronizing device coinprisinga rotary driving member, teeth therearoundya rotary driven member. a helical thread thereon, an axially-travel ling internally-threaded intermediate vmember on said thread, teeth around said intermediate member cooperating with said'driving teeth, a controlling member on said driven member adj acent to said thread,a subsidiary unidirectional drive between said driving member and said controlling member, said subsidiary unidirectional drive being positioned sothat the teeth of the-driving and intermediate members are located in definite rotational positions when the speed of the rotary driving member and the driven member synchronize, and means for couplingsaid controlling member and said intermediate member together, said coupling means perniitting the slight rotation necessary to take f up working clearances between the teeth of the intermediate and driving members and comprising tapered projections, and means I for locking said intermediate member to said driving member toobtain a solid drive, said locking means comprising a second ring of teeth around said intermediate member, a clutch element keyed to said driven member, means for axially sliding said clutch element, andteeth on said clutch element co-operating with said second ring of teeth on the intermediate member when its teeth and thoseof the driving member are in engagement.

7. An overrunning and'synchronizing device comprising a rotary-driving inember, teeth therearound, a rotary driven member, a helical thread thereon, an axially-travelling internally-threaded intermediate member on said thread, teeth around said intermediate member co-operatingwith said driving teeth,

a controlling memberon said driven member adjacent to said thread, a subsidiary unidirectional drive between said driving member and said controlling member, said'subsidiary unidirectional drive being positioned so that r the teeth of the drivingand interi'nediate members are located in definite rotational positions when the speed of the rotary driving member and the driven member synchronize, and comprising pawls on the controlling member co-operating with a second ring of teeth around the driving member, and means for couplingsaid controlling member and said intermediate member together, said. coupling means permitting-the slight rotation neces sary to take up working clearances between the teeth ofthe intermediate and drivlng members an d cg'imprising tapered projections.

a nd means for locking said intermediate member to said driving member to obtain a solld drive, said locking means comprising a second ring of teeth around said intermediate mcmber,a clutch element keyed to said driven member, means for axially sliding said clutch elemenaand teeth on said clutch element cooperating with said second ring of teeth on the intermediate member when its teeth and.

those of the driving member are'inengagement.

vice comprising a rotary driving member, teeth therearound, a rotary driven member, a helical thread thereon, an axially-travelling 'internally-threadeiil intermediate member onsaid thread, teeth around said intermediate member cooperating with said driving teeth, a controlling member on said driven member adjacent to said thread, a subsidiary unidirectional drive between said driving memher and said controlling member, said subsidiary unidire tional drive being positioned so that theteeth ot the driving and intermediate members are located in definite rotational positions when the speed of the rotary driving member and. the driven member synchronize, and comprising pawls on the con trollingmember co-operating with a second ring of teeth around the driving member,

and said controlling and comprising 8. An overrunnin'g and synchronizingdeandmeans for coupling said-controlling mem ber and said intermediate member together, said couplingmeans permitting the slight rotation'necessary to take up working clearances between the teeth of the intermediate and driving members and comprising tapered projections, means for lockingtsaid intermediate member to said driving member to ob- -tain a'solid' drive, said locking means com-- prising a second ring of teeth around said intermediatemember, a clutch element keyed to said driven member, means for axially sliding said clutch element, and teeth on said clutch element co-operatingwithsaid second ring of teeth on the intermediatcanember when its teeth and those of the driving member are in engagement, and means for eliminating contact between said pawls and said teeth. p

9. An overrunning and synchronizing d e-- vice comprising a rotary driving member,

teeth therearound, arotary driven member, a helical thread thereon, an axially-travelling internally-threadedintermediate member on v a said thread, teeth around said intermediate a controlling member on saiddriven member adjacent to said thread, a subsidiaiy'unidirectional drive between said driving member member, said subsidiary unidirectional drive being positioned so that the teeth of the driving and intermediate members are located in definite rotational positions when the'speed of-the-rot'ary driving member and-the driven member synchronize,

ber co-operating with a second ring of teeth around the driving member, and means for coupling said controlling member an'd hsaid intermediate member together,said coupling means permitting; the slight rotationnec es sary to take up workingclearances between member (ooperating with said driving teeth, 1

pawls onthe controlling memthe teeth of the intermediate and driving 1 members and comprising tapered projections,

means for locking said intermediate member to said driving member toobtain a solid drive,

said locking means comprising a second ring of teeth around said intermediate, member, a clutch element keyed to said driven membGIJTIGfiTIS for axially sliding said clutch element, and teeth on said clutch element co-opcrating with said second ring of teeth on the intermediate member when its teeth and those 5 of the driving member are in engagement, and means for eliminatingcontact between said pawls and said teeth, said eliminating means comprising an anti-friction bearing one race of which is on the driving member and the other and tongues on said fioating' member controling said pawls by reason of the inertia of the floating racevand flanged member and the slight drag between the races. I In testimony whereof, I. ahix my signature.

NOR-TON LEGGE.

on a flanged floating member, 

